Walgreens has partnered with UnitedHealth Group's MedExpress urgent care centers in 16 pilot markets to more closely link primary care with the drugstore chain's pharmacies. These pictured connected facilities are in Elkins, West Virginia. (MedExpress/UnitedHealth Group photo)

A partnership between UnitedHealth Group’s MedExpress urgent care centers and Walgreens Boots Alliance to connect primary care with the corner drugstore has grown to 15 locations.

For now, the effort between the Optum healthcare provider unit of the nation’s largest health insurer and the nation’s largest drugstore chain is a pilot project. But the venture is creating buzz among investors as rival pharmacy chain CVS Health has promised primary care pilots of its own after it completes its $69 billion acquisition of Aetna, the nation’s third-largest health insurer.

Though the Walgreens store and the MedExpress center each have their own entrance there is a door inside connecting the urgent care center with the drugstore, so a medical provider can guide a patient to either facility depending on their prescription or other needs.

The retail approach of UnitedHealth's Optum healthcare delivery unit also includes urgent care facilities, ambulatory surgery centers, doctor practices and related locally based community health clinics. UnitedHealth and Walgreens said the results of the pilot are “not near final” but they have hopes the MedExpress urgent care model with an adjunct pharmacy will lead to higher quality care.

“We see this as an innovative concept in the convenient care/retail space, and another potential opportunity to provide more convenient access to health care services in the community, while expanding health care networks with our partners,” Walgreens said in a statement. “As with any pilot program, we will look to gather key learnings and insights over the course of the pilot before making any decisions regarding further expansion.”

Urgent care, also known as immediate care, is similar to retail health clinics operated by Walgreens, CVS and Walmart in that they are open daily, evenings and on weekends to treat routine health needs. But urgent care centers also generally offer more in the form of a board-certified physician plus additional services such as X-rays for potential broken bones.

Though UnitedHealth is working with Walgreens on a pilot, the insurer isn’t ruling out working with other drugstore chains, retailers and health systems on additional or similar ventures. UnitedHealth Group’s Optum health services unit is now in half of the 75 U.S. markets executives have targeted for expansion, executives said last month.

UnitedHealth’s retail approach became an even bigger focus last year after Optum agreed to spend nearly $5 billion to buy DaVita Medical Group. That deal will add a large network of nearly 300 medical clinics that treat 1.7 million patients annually.